Objective: Dengue haemorrhagic fever (DHF) is a major problem in Indonesia. In the last five months, there have been outbreaks in some rural area, included East Sumba. An increasing number of DHF cases are associated with unsual presentations, except for pleural effusions, that can lead to respiratory failure. The extent of plasma effusion in dengue can be identified by the pleural effusion index (PEI). Some of case acute respiratory distress syndrome in DHF were treated with ventilatory assistance. This research aimed to study the correlation between PEI with incidences of respiratory failure patient that present in ventilatory assistance in pediatric DHF cases in Umbu Rara Meha General Hospital.                                                                                                                           Method: This research record-based study conducted in district of Waingapu, East Nusa Tenggara. Design of research are cross-sectional, using retrospective method study. Required data was taken from medical records of pediatric patients and was confirmed by clinical, laboratory findings, and radiology chest x-ray manifestations from Oktober 2018 to March 2019. Data were collected from Umbu Rara Meha General Hospital and analyzed using nonparametric test Mann Whitney analysis.                                 Result: This study was involved by 67 pediatric patients were diagnosed as DHF and suggested had pleural effusion. 10 patients of them were treated with mechanical ventilation. PEI was counted and showed that there was a significant correlation between PEI with ventilatory assistance (p= 0.002). Significant PEI cut off point using ROC resulting PEI value >65% will more likely risk for have respiratory failure and need to treat with mechanical ventilator.                                                                          Conclusion: DHF patient with PEI >65% was a risk for have respiratory failure and need to treated with ventilatory assistance.